#This electron accelerator is smaller than a grain of rice Stanford university rightoriginal Studyposted by Mike Ross-Stanford on September 30 2013researchers have used a laser to accelerate electrons at a rate 10 times higher than conventional technology
in a nanostructured glass chip smaller than a grain of rice. e still have a number of challenges before this technology becomes practical for real-world use
but eventually it would substantially reduce the size and cost of future high-energy particle colliders for exploring the world of fundamental particles
and forcessays Joel England a physicist with the US Department of energy s SLAC National Accelerator Laboratory at Stanford university who led the experiments. t could also help enable compact accelerators and X-ray devices for security
scanning medical therapy and imaging and research in biology and materials science. ecause it employs commercial lasers
and low-cost mass-production techniques the researchers believe it will set the stage for new generations of abletopaccelerators.
or amount of energy gained per length of the accelerator of 300 million electronvolts per meter.
That s roughly 10 times the acceleration provided by the current SLAC linear accelerator. ur ultimate goal for this structure is one billion electronvolts per meter and we re already one-third of the way in our first experimentsaid
Stanford applied physics Professor Robert Byer the principal investigator for this research. Today s accelerators use microwaves to boost the energy of electrons.
Researchers have been looking for more economical alternatives and this new technique which uses ultrafast lasers to drive the accelerator is a leading candidate.
Then any additional acceleration increases their energy but not their speed; this is the challenging part.
In the accelerator-on-a-chip experiments electrons are accelerated first to near light-speed in a conventional accelerator.
Then they are focused into a tiny half-micron-high channel within a glass chip just half a millimeter long.
The channel had earlier been patterned with precisely spaced nanoscale ridges. Infrared laser light shining on the pattern generates electrical fields that interact with the electrons in the channel to boost their energy.
View animation for more detail. Turning the accelerator on a chip into a full-fledged tabletop accelerator will require a more compact way to get the electrons up to speed before they enter the device.
A collaborating research group in Germany led by Peter Hommelhoff at Friedrich Alexander University and the Max Planck Institute of Quantum Optics has been looking for such a solution.
It simultaneously reports in Physical Review Letters its success in using a laser to accelerate lower energy electrons.
Another possible application is small portable X-ray sources to improve medical care for people injured in combat as well as to provide more affordable medical imaging for hospitals and laboratories.
Primary funding for this research is from the US Department of energy Office of Science. The study s lead authors were Stanford graduate students Edgar Peralta and Ken Soong.
Additional contributors included researchers from the University of California-Los angeles and Tech-X Corp. in Boulder Colo.
Source: Stanford Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
#To avert mass extinction, is genetic engineering the best option? Cornell University rightoriginal Studyposted by Blaine Friedlander-Cornell on September 30 2013with estimates that 15 to 40 percent of the world s species will be lost over the next 40 years due to warming
and habitat loss researchers are considering the option of a genetic rescue. The technique would involve escuing a target population
or species with adaptive alleles or gene variants using genetic engineeringwrite Josh Donlan Cornell visiting fellow in ecology and evolutionary biology and his colleagues.
The method is n increasingly viable...option which we call facilitated adaptation but it has been little discussedadds Donlan co-author of an article about the topic published in the journal Nature.
To avert mass extinctions the group thinks that three options each with its own set of challenges complications
and risks exist. They are: The Nature commentary draws from a recent workshop cological and Genomic Exploration of Environmental Changethat occurred in March where scientists met to understand issues surrounding climate change adaptation.
In those spirited discussions a hot question emerged: is managed relocation of animal and plant species really the only approach to averting extinction?
Averting climate change altogether would be a preferableâ##albeit unlikelyâ##outcome. The scientists fear that implementing genetic solutions could potentially deter other climate change action. serious concern is that even the possibility of using genetic-engineering tools to rescue biodiversity will encourage inaction with regard to climate change.
Before genetic engineering can be entertained seriously as a tool for preserving biodiversity conservationists need to agree on the types of scenario for which facilitated adaptation managed relocation
and other adaptation strategies might be appropriate and where such strategies are likely to fail
#Tiny optical tuning fork fits on a chip California Institute of technology rightoriginal Studyposted by Jessica Stoller-Conrad-Caltech on September 27 2013researchers have created an optical equivalent of a tuning fork that can help steady electronic currents
needed to power high-end electronics and stabilize signals of high-quality lasers. Itâ#the first time such a device has been miniaturized to fit on a chip
and may pave the way for improvements in high-speed communication navigation and remote sensing. hen you re tuning a piano a tuning fork gives a standardized pitch or reference sound frequency;
in optical resonators the pitch corresponds to the color or wavelength of the lightsays Kerry Vahala professor of information science and technology and applied physics at the California Institute of technology (Caltech.
and electronic devices when it is used as a reference. good tuning fork controls the release of its acoustical energy ringing just one pitch at a particular sound frequency for a long timeâ##a sustaining property called the quality factor.
and his colleagues transferred this concept to their optical resonator focusing on the optical quality factor and other elements that affect frequency stability.
The researchers were able to stabilize the light s frequency by developing a silica glass chip resonator with a specially designed path for the photons in the shape of
what is called an Archimedean spiral. sing this shape allows the longest path in the smallest area on a chip.
Frequency instability stems from energy surges within the optical resonatorâ##which are unavoidable due to the laws of thermodynamics.
Because the new resonator has a longer path the energy changes are diluted so the power surges are dampenedâ##greatly improving the consistency
and quality of the resonator s reference signal which in turn improves the quality of the electronic or optical device.
In the new design photons are applied to an outer ring of the spiraled resonator with a tiny light-dispensing optic fiber;
In combination with the resonator a special guide for the light was used losing 100 times less energy than the average chip-based device.
In addition to its use as a frequency reference for lasers a reference cavity could one day play a role equivalent to that of the ubiquitous quartz crystal in electronics.
Most electronics systems use a device called an oscillator to provide power at very precise frequencies.
In the past several years optical-based oscillatorsâ##which require optical reference cavitiesâ##have become better than electronic oscillators at delivering stable microwave and radio frequencies.
While these optical oscillators are currently too large for use in small electronics there is an effort under way to miniaturize their key subcomponentsâ##like Vahala s chip-based reference cavity. miniaturized optical oscillator will represent a shift in the traditional
and electronics. urrently electronics perform signal processing while photonics rule in transporting information from one place to another over fiber-optic cable.
Eventually oscillators in high-performance electronics systems while outwardly appearing to be electronic devices will internally be purely opticalvahala says. he technology that Kerry
and received funding support from the Defense Advanced Research Projects Agency Caltech s Kavli Nanoscience Institute and the Institute for Quantum Information and Matter an
#Does this carbon nanotube computer spell the end for silicon? Stanford university rightoriginal Studyposted by Tom Abate-Stanford on September 27 2013engineers have built a basic computer using carbon nanotubes a success that points to a potentially faster more efficient alternative to silicon chips.
The achievement is reported in an article on the cover of the journal Nature. eople have been talking about a new era of carbon nanotube electronics moving beyond siliconsays Subhasish Mitra an electrical engineer
and computer scientist at Stanford university who co-led the work. ut there have been few demonstrations of complete digital systems using this exciting technology.
Here is the proof. xperts say the achievement will galvanize efforts to find successors to silicon chips which could soon encounter physical limits that might prevent them from delivering smaller faster cheaper electronic devices. arbon nanotubes CNTS have long been considered as a potential successor to the silicon transistorsays Professor
Jan Rabaey a world expert on electronic circuits and systems at the University of California Berkeley.
But until now it hasn t been clear that CNTS a semiconductor material could fulfill those expectations. here is no question that this will get the attention of researchers in the semiconductor community
and entice them to explore how this technology can lead to smaller more energy-efficient processors in the next decaderabaey says.
Mihail Roco a senior advisor for nanotechnology at the National Science Foundation called the work n important scientific breakthrough. t was roughly 15 years ago that carbon nanotubes were fashioned first into transistors the on-off switches
at the heart of digital electronic systems. But a bedeviling array of imperfections in these carbon nanotubes has frustrated long efforts to build complex circuits using CNTS.
Professor Giovanni De Micheli director of the Institute of Electrical engineering at Ã#cole Polytechnique FÃ dã rale de Lausanne in Switzerland highlighted two key contributions the Stanford
team has made to this worldwide effort. irst they put in place a process for fabricating CNT-based circuitsde Micheli says. econd they built a simple
but effective circuit that shows that computation is doable using CNTS. s Mitra says: t s not just about the CNT COMPUTER.
It s about a change in directions that shows you can build something real using nanotechnologies that move beyond silicon
and its cousins. uch concerns arise from the demands that designers place upon semiconductors and their fundamental workhorse unit those on-off switches known as transistors.
For decades progress in electronics has meant shrinking the size of each transistor to pack more transistors on a chip.
But as transistors become tinier they waste more power and generate more heatâ##all in a smaller and smaller space as evidenced by the warmth emanating from the bottom of a laptop.
Many researchers believe that this power-wasting phenomenon could spell the end of Moore s Law named for Intel Corp. cofounder Gordon Moore who predicted in 1965 that the density of transistors would double roughly every two years
leading to smaller faster and as it turned out cheaper electronics. But smaller faster and cheaper has meant also smaller faster and hotter. nergy dissipation of silicon-based systems has been a major concernsays Anantha Chandrakasan head of electrical engineering and computer science at MIT and a world
leader in chip research. He called the Stanford work major benchmarkin moving CNTS toward practical use.
CNTS are long chains of carbon atoms that are extremely efficient at conducting and controlling electricity.
They are so thinâ##thousands of CNTS could fit side by side in a human hairâ##that it takes very little energy to switch them off according to Wong a co-author of the paper. hink of it as stepping on a garden hosewong explains. he thinner the hose the easier it is to shut off the flow. n theory this combination
of efficient conductivity and low-power switching make carbon nanotubes excellent candidates to serve as electronic transistors. NTS could take us at least an order of magnitude in performance beyond where you can project silicon could take uswong said.
But inherent imperfections have stood in the way of putting this promising material to practical use.
First CNTS do not necessarily grow in neat parallel lines as chipmakers would like. Over time researchers have devised tricks to grow 99.5 percent of CNTS in straight lines.
But with billions of nanotubes on a chip even a tiny degree of misaligned tubes could cause errors
so that problem remained. A second type of imperfection has stymied also CNT technology. Depending on how the CNTS grow a fraction of these carbon nanotubes can end up behaving like metallic wires that always conduct electricity instead of acting like semiconductors that can be switched off.
Since mass production is the eventual goal researchers had to find ways to deal with misaligned
and/or metallic CNTS without having to hunt for them like needles in a haystack. e needed a way to design circuits without having to look for imperfections
or even know where they weremitra says. The Stanford paper describes a two-pronged approach that the authors call an mperfection-immune design. o eliminate the wire-like
or metallic nanotubes the Stanford team switched off all the good CNTS. Then they pumped the semiconductor circuit full of electricity.
All of that electricity concentrated in the metallic nanotubes which grew so hot that they burned up
and literally vaporized into tiny puffs of carbon dioxide. This sophisticated technique eliminated the metallic CNTS in the circuit.
Bypassing the misaligned nanotubes required even greater subtlety. The Stanford researchers created a powerful algorithm that maps out a circuit layout that is guaranteed to work no matter
whether or where CNTS might be askew. his imperfections-immune design technique makes this discovery truly exemplarysays Sankar Basu a program director at the National Science Foundation.
The Stanford team used this imperfection-immune design to assemble a basic computer with 178 transistors a limit imposed by the fact that they used the university s chip-making facilities rather than an industrial fabrication process.
Their CNT COMPUTER performed tasks such as counting and number sorting. It runs a basic operating system that allows it to swap between these processes.
In a demonstration of its potential the researchers also showed that the CNT COMPUTER could run MIPS a commercial instruction set developed in the early 1980s by then Stanford engineering professor and now university President John Hennessy.
Though it could take years to mature the Stanford approach points toward the possibility of industrial-scale production of carbon nanotube semiconductors according to Naresh Shanbhag a professor at the University of Illinois at Urbana-Champaign
and director of SONIC a consortium of next-generation chip design research. he Wong/Mitra paper demonstrates the promise of CNTS in designing complex computing systemsshanbhag says adding that this will motivate researchers elsewhere toward greater efforts in chip design
beyond silicon. hese are initial necessary steps in taking carbon nanotubes from the chemistry lab to a real environmentsays Supratik Guha director of physical sciences for IBM s Thomas J. Watson Research center
and a world leader in CNT research. The National Science Foundation SONIC the Stanford Graduate Fellowship and the Hertz Foundation Fellowship funded the work.
Source: Stanford Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
#Is this mineral to blame for deep earthquakes? University of Chicago rightoriginal Studyposted by Steve Koppes-Chicago on September 25 2013scientists are closer to understanding deep earthquakes which occur
when tectonics drive the oceanic crust under continental plates. Their new research is a large step toward replicating the full power of these earthquakesâ##to learn what sets them off
and how they unleash their power off the coasts of the western United states Russia and Japan.
The team used an X-ray facility that can replicate high pressure and temperature while allowing scientists to peer deep into material to trace the propagation of cracks
and shock waves. e are capturing the physics of deep earthquakessays Yanbin Wang a senior scientist at the University of Chicago who helps run the X-ray facility at Argonne National Laboratory where the research occurred. ur experiments show that for the first time laboratory
-triggered brittle failures during the olivine-spinel (mineral) phase transformation has many similar features to deep earthquakes. ang
and a team of scientists simulated deep earthquakes by using a pressure of 5 gigapascals more than double the previous studies of 2 GPA.
For comparison pressure of 5 GPA is 4. 9 million times the pressure at sea level.
At this pressure rock should be squeezed too tight to rapture and erupt into violent earthquakes yet it does.
And that has puzzled scientists since the phenomenon of deep earthquakes was discovered nearly 100 years ago.
Interest spiked with the May 24 2013 eruption in the waters near Russia of the world s strongest deep earthquakeâ##roughly five times the power of the great San francisco quake of 1906.
These deep earthquakes occur in older and colder areas of the oceanic plate that gets pushed into the earth s mantle.
It has been speculated that the earthquakes are triggered when a mineral common in the upper mantle olivine undergoes a transformation that weakens the whole rock temporarily causing it to fail. ur current goal is to understand why
and how deep earthquakes happen. We are not at a stage to predict them yet.
It is still a long way to gowang says. The work was conducted at the Geosoilenvirocars beamline operated by University of Chicago at the Advanced Photon Source housed at Argonne.
More than 20 years ago geologist Harry Green of University of California Riverside and colleagues discovered a high-pressure failure mechanism that they proposed then was sought the long mechanism of very deep earthquakes (earthquakes
occurring at a depth of more than 400 kilometers/248.5 miles. The result was controversial because seismologists could not find a seismic signal in the Earth that could confirm the results.
Seismologists have now found the critical evidence. Indeed beneath Japan they have imaged even the telltale evidence
and showed that it coincides with the locations of deep earthquakes. In the September 20 issue of Science Green and colleagues explain how to simulate these earthquakes. e confirmed essentially all aspects of our earlier experimental work
and extended the conditions to significantly higher pressuregreen says. The ability to do such experiments allows scientists like Green to simulate the appropriate conditions within the Earth
and record and analyze the arthquakesin their small samples in real time thus providing the strongest evidence yet that this is the mechanism by
which earthquakes happen at hundreds of kilometers depth. The origin of deep earthquakes fundamentally differs from that of shallow earthquakes (earthquakes occurring at less than a depth of 50 kilometers/31 miles.
In the case of shallow earthquakes theories of rock fracture rely on the properties of coalescing cracks
and friction. ut as pressure and temperature increase with depth intracrystalline plasticity dominates the deformation regime
so that rocks yield by creep or flow rather than by the kind of brittle fracturing we see at smaller depthsgreen explains. oreover at depths of more than 400 kilometers the mineral olivine is no longer stable
and undergoes a transformation resulting in spinel a mineral of higher density. he research team focused on the role that phase transformations of olivine might play in triggering deep earthquakes.
They performed laboratory deformation experiments on olivine at high pressure and found the arthquakesonly within a narrow temperature range that simulates conditions where the real earthquakes occur in Earth. sing synchrotron X-rays to aid our observations we found that fractures nucleate at the onset of the olivine to spinel transitiongreen says. urther these fractures propagate dynamically
so that intense acoustic emissions are generated. These phase transitions in olivine we argue in our research paper provide an attractive mechanism for how very deep earthquakes take place. ang says researchers next goal is to study the material silicate olivine which requires much higher pressures.
The Institut National des Sciences de l Univers and L Agence Nationale de la Recherche and the National Science Foundation funded the work.
The US Department of energy Office of Science funded the use of the Advanced Photon Source. Study authors contributed from the Ecole Normale Supã rieure in France Universitã de Granoble in France the University of Chicago and UMET CNRS â##Universitã Lille 1 and UC Riverside.
Source: University of Chicagoyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license e
#Cell close ups reveal how plants get bigger Iowa State university Penn State rightoriginal Studyposted by Mike Krapfl-Iowa State on September 25 2013a new supersensitive instrument lets scientists see where a protein
binds to plant cell walls which loosens them and makes growth possible. Researchers say the discovery could one day lead to bigger harvests of biomass for renewable energy.
Finding that binding target has been a major challenge for structural biologists. That s because there are only tiny amounts of the protein involved in cell growth
and because cell walls are very complex says Mei Hong one of the project s lead researchers a professor of chemistry at Iowa State university.
A paper describing the discovery appears early online in the Proceedings of the National Academy of Sciences.
Hong has used long solid-state nuclear magnetic resonance (NMR) spectroscopy to study structural biology including the mechanism used by the flu virus to infect host cells.
But in this case that technology wasn t sensitive enough to identify the binding site of the expansin protein.
So the researchers##working with specialists from the Bruker Biospin Corp. a manufacturer of scientific instruments##used a technology called dynamic nuclear polarization (DNP) to enhance the sensitivity of spectroscopy instruments.
The researchers studied Arabidopsis thaliana often used as a model subject in plant science studies and found the protein binds to specific regions of cellulose microfibrils the long parallel chains of cellulose that make up plant cell walls.
and we are quite happy that the DNP NMR technology is so useful for understanding this plant biochemistry questionsays Hong also a faculty scientist with the US Department of energy s Ames Laboratory.
Knowing where expansin binds to cell walls ight help biochemists design more potent expansins to loosen the cell wall
and thus better harvest bioenergy. ong and Daniel Cosgrove professor and chair in biology at Penn State are the lead authors.
and Broker Biospin Corp. The US Department of energy supported the work. Source: Iowa Stat
#Densest galaxy is jam-packed with stars Michigan State university right Original Studyposted by Tom Oswald-Michigan State on September 25 2013 Astronomers have discovered the densest galaxy in the nearby universe.
Now imagine as many as 10000 of our suns crammed into that relatively small space. his galaxy is more massive than any ultra-compact drawfs of comparable sizesays Jay Strader assistant professor of physics
#Colonies of wired microbes turn sewage into electricity Stanford university rightoriginal Studyposted by Tom Abate-Stanford on September 19 2013a new way to generate electricity from sewage uses naturally occurring ired microbesas mini power plants
to produce electricity as they digest plant and animal waste. Scientists hope the icrobial batterycan be used in places such as sewage treatment plants
or to break down organic pollutants in the ead zonesof lakes and coastal waters where fertilizer runoff and other organic waste can deplete oxygen levels
and suffocate marine life. At the moment however the laboratory prototype is about the size of A d-cell battery
and looks like a chemistry experiment with two electrodes one positive the other negative plunged into a bottle of wastewater.
Inside that murky vial attached to the negative electrode bacteria feast on particles of organic waste
and produce electricity that is captured by the battery s positive electrode. e call it fishing for electronssays Craig Criddle a professor in the department of civil and environmental engineering at Stanford university.
Scientists have known long of the existence of what they call exoelectrogenic microbesâ##organisms that evolved in airless environments
and developed the ability to react with oxide minerals rather than breathe oxygen as we do to convert organic nutrients into biological fuel.
Over the last dozen years or so several research groups have tried various ways to use these microbes as bio-generators
but tapping this energy efficiently has proven challenging. What is new about the microbial battery is a simple yet efficient design that puts these exoelectrogenic bacteria to work.
As reported in the Proceedings of the National Academy of Sciences at the battery s negative electrode colonies of wired microbes cling to carbon filaments that serve as efficient electrical conductors.
Using a scanning electron microscope the Stanford team captured images of these microbes attaching milky tendrils to the carbon filaments. ou can see that the microbes make nanowires to dump off their excess electronscriddle says.
To put the images into perspective about 100 of these microbes could fit side by side in the width of a human hair.
and convert it into biological fuel their excess electrons flow into the carbon filaments and across to the positive electrode
After a day or so the positive electrode has absorbed a full load of electrons and has largely been converted into silver says Xing Xie an interdisciplinary researcher.
At that point it is removed from the battery and re-oxidized back to silver oxide releasing the stored electrons.
Engineers estimate that the microbial battery can extract about 30 percent of the potential energy locked up in wastewater.
That is roughly the same efficiency at which the best commercially available solar cells convert sunlight into electricity.
Of course there is far less energy potential in wastewater. Even so the microbial battery is worth pursuing because it could offset some of the electricity now used to treat wastewater.
That use currently accounts for about 3 percent of the total electrical load in developed nations.
Most of this electricity goes toward pumping air into wastewater at conventional treatment plants where ordinary bacteria use oxygen in the course of digestion just like humans and other animals.
Looking ahead the engineers say their biggest challenge will be finding a cheap but efficient material for the positive node. e demonstrated the principle using silver oxide
but silver is too expensive for use at large scalesays Yi Cui an associate professor of materials science and engineering. hough the search is under way for a more practical material finding a substitute will take time. ource:
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